> do-sessions is gone and *session-db* is internal to hunchentoot

Yes, see the section about customizing session behaviour.  You can
insert your own session-db method.  Or, if you absolutely want to
iterate globally across all sessions, you can catch the return value
of the default method.

> *catch-errors-p* is gone and *http-error-handler* is called with HTTP code
> only (for error page customisation only?). Not-catching lisp errors by
> hunchentoot was excellent for debugging

See the recent discussion on the list.  The next release will provide
some changes w.r.t. error handling and debugging.

> calling reset-sessions outside of request context complains about *acceptor*
> not being set

Yes, that's a consequence of making the session behaviour
customizable.  Is this a big problem?